Police are now reconsidering their theory that a third man was driving accused Dellen Millard’s vehicle before the death of the Ancaster man.

Det.Sgt Matt Matt Kavanagh discusses the Timothy Bosma missing man case at a news conference in Hamilton, Ont., Tuesday, May 14, 2013. On Thursday he told the Star he's not sure if there is a third suspect.

The lead investigator in the murder of Tim Bosma said police are considering the possibility there is no third suspect.

Det.-Sgt. Matt Kavanagh, of the Hamilton police homicide squad, told the Star he is not sure whether there are three suspects responsible for kidnapping and then killing the 32-year-old Ancaster father, who left his home on May 6 for a test drive and never returned.

Dellen Millard, 27, and Mark Smich, 25, have been charged with first-degree murder.

Police earlier alleged the two men climbed into Bosma’s 2007 Dodge Ram and were then followed by a second car — Millard’s dark blue GMC Yukon. A third suspect was believed to be the person driving that second car.

Kavanagh now says police are not sure whether Smich, who is said to have been in the back seat of the truck while Millard was driving, exited that vehicle after leaving Bosma’s home and got into the driver’s seat of the Yukon.

“That is possible right now, yes, but I’m not going to commit either way,” Kavanagh said.

If there is a third suspect, Kavanagh said, police do not have any leads on who it might be.

Millard’s girlfriend, whose identity is protected by a court-ordered publication ban, is not believed to be involved, the detective said.

“Millard’s girlfriend has been cleared of that,” he said.

As for the rest of the names on a long list of people Millard and Smich have been ordered not to contact — including several known friends — Kavanagh would not distinguish between whether they are potential witnesses or suspects.

“They could be both,” he said.

The Star has revealed that Millard transferred three properties to his mother in trust in the days following his arrest. But Kavanagh said those transfers are not part of their investigation.

“It doesn’t form part of the evidence in my case,” he said.

Both Millard and Smich have said through their lawyers that they intend to plead not guilty to the murder charge.

Toronto police are also investigating the June 2012 disappearance of Toronto resident Laura Babcock and the apparent suicide in November 2012 of Millard’s father, Wayne, in connection to Millard.